At first glance, this question might seem like a no-brainer. After all, if you have a cement mixer drum rated for 10 yards of concrete, it stands to reason that it can hold 10 yards, right? Actually, it isn’t quite that simple. Let us explain.
A 10-yard drum can theoretically hold about 14 yards total, but shouldn’t be filled past 10 yards. This is because “breathing room” plays a crucial role when mixing and pouring concrete. As a truck’s drum turns, it moves the ingredients inside around, bringing every element together into a consistent blend. It’s much like a mixing bowl filled to maximum capacity. Leave too little space inside, and you risk allowing pockets of ingredients — in this case sand, cement or aggregate — to remain “clumped” together, not fully incorporating into the overall concrete blend. Not only can this result in an inconsistent final product that is difficult to pour and smooth, but it can compromise the strength of the finished concrete.
The need for extra space doesn’t end there. While it might seem fairly obvious, a drum filled to the brim has a tendency to allow concrete to spill out the open back and on to roadways, sidewalks and nearby objects. Considering concrete’s fairly permanent nature once dried and set, such spillage can have messy, cost-prohibitive repercussions.
Curious to learn more? Visit our FAQ page and click on the write-up entitled “What Does General Chipping Consider a ‘Full Load?’” to delve a bit deeper into the topic. Truck manufacturers can also offer helpful information into their particular makes and models. McNeilus and Shumaker Industries are great places to start. Of course, you’re also free to contact our team at General Chipping. Give us a call at 1.866.343.8295, or visit our Contact page to get in touch with our crew directly. We’re always glad to help.